A CD-ROM (compact disc read only memory) is known as an information recording medium for program data, audio information, and video information. Such a CD-ROM has an information capacity of 540 MB and is widely used as a distribution medium for program data, audio information, and video information. Information recorded in the CD-ROM is retrieved and processed by a personal computer incorporating a CD-ROM drive, for example.
In recent years, with the enhancement in the processing environments of audio information and video information on personal computers, audio information and video information stored in a CD-ROM can be directly output on a personal computer. When video information is stored in a CD-ROM, it is necessary to conduct digital compression to the video information and to store the compressed video information in the CD-ROM, since the video information has a large amount of data. An MPEG1 (moving picture experts group 1) method, for example, is used as a method for compressing video information where the transfer rate of CD-ROMs of 1.2 Mbps is available. The MPEG1 method employs interframe compression as its main compression principle. Video information is a moving picture composed of still pictures called "several ten frames per second". In the interframe compression, sufficient data for reproducing a still picture is prepared for one frame every several frames. For the remaining frames, only data representing the difference from the frame provided with sufficient data is prepared, thus to compress the required data amount.
In the MPEG1 method, in reality, audio information which is mixed in video information is also compressed together with the video information, generating digital data called an MPEG system stream. It is therefore difficult to unconditionally distinguish the video information from the audio information in the digital data. Such data including video information and audio information as well as information required for reproducing the data mixed therein is often called data having an audio and video (AV) data configuration or AV data. Herein, such data including video information and audio information mixed therein is referred to as "AV data".
In the MPEG1 method, the horizontal resolution of images is on the order of 250 lines. This is not sufficiently high for applications requiring high-quality images such as movie applications. A laser disc (LD) having a horizontal resolution of 430 lines has conventionally been used as a medium for storing such applications requiring high-quality images. The LD however stores video information in an analog form. In recent years, a digital video disk (DVD) has been proposed as a new optical disk which stores data in a digital form so as to be processed by personal computers and has a level of resolution required for movie application. The DVD has an information capacity eight times or more of that of the CD-ROM and realizes a data transmission rate five times or more of that of the CD-ROM. The DVD employs a MPEG2 method as the method for compressing video information which realizes a horizontal resolution of 450 lines or more to obtain high-quality moving pictures required for movie applications.
Hereinbelow, a personal computer incorporating a CD-ROM drive as a conventional information processing apparatus will be described with reference to FIGS. 30 and 31, where AV data stored in the CD-ROM is directly reproduced and output by the personal computer itself.
FIG. 31 is a view showing a configuration of a conventional personal computer having a CD-ROM drive. In FIG. 31, reference numeral 2401 denotes a CD-ROM which records an MPEG stream of AV data managed by a filing system. Reference numeral 2402 denotes a disk reproduction drive which reproduces the optical disk 2401 and outputs digital data of a designated sector number. Reference numeral 2403 denotes an AV signal processor which conducts a predetermined decompressing processing to the MPEG stream, converts it into an analog audio signal and a digital video signal, and outputs the results. The analog audio signal is audibly output via a speaker 2403S.
Reference numeral 2404 denotes a recording section which is a hard disk. Reference numeral 2405 denotes an input section which has a mouse 2405K and a keyboard 2405M and receives instructions form the external. Reference numeral 2406 denotes an I/O bus.
Reference numeral 2407 denotes a video signal processor synthesizes a digital video signal output from the AV signal processor 2403 with a video signal for display generated inside the personal computer and outputs the results as an analog video signal to a display device 2407D. The analog video signal is visually output by the display device 2407D. The video signal processor 2407 is typically a video card. A controller 2408 includes a CPU 2408C, a bus interface (I/F) 2408I, and a main memory 2408M which are connected with one another by a processor bus 2408B. An operating system (OS) program for managing the filing system and a reproduction control program as an application operated on the OS for reproducing AV data in the optical disk 2401 in accordance with the user's instructions are loaded in the controller 2408. A graphic user interface generated according to the reproduction control program loaded in the controller 2408 is displayed on the external display device connected to the AV signal processor 2403.
FIG. 30 is a front view of the display device. Reference numeral 2301 denotes the display device. Reference numeral 2302 denotes a display region. Reference numeral 2303 denotes a MPEG moving picture display region. Reference numeral 2304 denotes a control panel display region. Reference numeral 2305 denotes a graphic for providing a feedback of the coordinates designated on the screen by the keyboard 2405K and the mouse 2405M connected to the input section 2405.
The operation of the conventional CD-ROM drive incorporated personal computer with the above configuration will be described.
Since the overall operation of the personal computer is the same as that of general personal computers (e.g., PC-AT compatible machines), detailed description thereof is omitted here. Only the operations relating to the present invention, i.e., the operation for reproducing and outputting AV data in the optical disk 2401 and the operation for copying a file in the optical disk 2401 to the recording section 2404 will be described.
First, the operation for reproducing and outputting AV data will be described. When the user designates a control panel indicating "reproduction start" displayed on the control panel display region 2304 by the use of the mouse 2405M connected to the input section, the controller 2408 interprets the input as the reproduction control command indicating "reproduction start" from the input coordinates and calculates a recording address of a file storing a predetermined MPEG stream for reproduction start in the optical disk 2401 in accordance with the filing system. The controller 2408 sends a data read command (READ #Address) to the disk reproduction drive 2402 to read data in the calculated recording address, and outputs the read digital data to the AV signal processor 2403 in accordance with a data write command (WRITE). The AV signal processor 2403 processes the input MPEG stream of digital data in a predetermined manner and converts the data into an analog audio signal and a digital video signal and outputs the results. The analog audio signal is audibly output via the speaker 2403S. The digital video signal is input into the video signal processor 2407, where the digital video signal is synthesized with video information for display generated inside the computer and displayed by the display device 2407D as images.
Thus, the MPEG stream reproduced from the optical disk 2401 is displayed in the MPEG moving picture display region 2303 of the display device 2407D.
The operation for copying a file recorded in the optical disk 2401 to the recording section 2404 will be described. The input section 2405 receives a command input by the user via the keyboard 2405K. When the input command is a copy command requesting to copy a file in the optical disk 2401 to the recording section 2404, the controller 2408 calculates the recording address of the file to be read in the optical disk 2401 in accordance with the filing system. After calculating the recording address, the controller 2408 sends a data read command (READ #Address) to the disk reproduction drive 2402 to read digital data in the calculated recording address, and sends a data write command (WRITE) to the recording section 2404 so that the data is output and held in the recording section 2404.
With the above configuration, however, digital data retrieved from the optical disk 2401 is uniformly processed by the controller 2408 without distinguishing AV data from others. This makes it difficult to perform a copyright protection processing on AV data.
The "copyright protection processing" as used herein refers to a processing where a copyrighter of AV data specifies the conditions for the use of the AV data in an information processing apparatus. More specifically, the copyrighter may permit only reproduction/output of the AV data (i.e., prohibit copying of the AV data to a hard disk and the like) or permit both reproduction/output and copying of the AV data.
With the above conventional configuration, if the user mistakenly inputs a copy command requesting to copy a file including AV data of which copying is not permitted to the recording section 2404, the disk reproduction drive 2402 receives the same data read command (READ #Address) as that received when the video data reproduction command is input. As a result, the AV data is read and stored in the recording section 2404 as is done for other general data.
As another problem, the operation of the controller 2408 is dynamically determined by loading the OS and the reproduction control program. If the loaded program has an error, an erroneous operation of copying a file including AV data may arise, irrespective of the operation by the user.
For the above reasons, there exists a possibility that AV data of which copying is not permitted may be secondarily stored in a hard disk and the like. Therefore, the copyright of such AV data is not completely protected. This problem is especially serious for such applications that require high horizontal resolution to obtain high-quality images. To take precautions against this problem, authors of such applications may set higher prices to compensate expected damage due to infringement of the copyright, or authors may even give up the idea of producing movie applications and the like of which copyright is extraordinarily valuable. As a result, a sound market where a number of applications are presented to the users at appropriate prices is not expected, which is greatly disadvantageous for the users.
In order to overcome the above problem, an objective of the present invention is to provide data transmitting device/method, a data receiving device, an information processing apparatus, and an information recording medium, where AV data recorded in the information recording medium can be audibly and visually output by a personal computer and, when digital data retrieved from the information recording medium is AV data, the AV data is subjected to a copyright protection processing to protect the AV data from being illegally copied due to an erroneous operation by the user or an erroneous program. According to the present invention, since the protection of the copyright of applications is ensured, a number of applications are urged to be circulated in the market at appropriate prices, and thus advantages for the users are secured.